Phase coexistence and connectivity in the apical membrane of polarized epithelial cells

摘要: Although it is well described in model membranes, little known about phase separation biological membranes. Here, we provide evidence for a coexistence of at least two different lipid bilayer phases the apical plasma membrane epithelial cells. Phase connectivity was assessed by measuring long-range diffusion several proteins fluorescence recovery after photobleaching polarized cell lines and one fibroblast line. In contrast to membrane, which all diffused with similar characteristics, cells could be divided into groups according their characteristics. At room temperature (≈25°C), group showed fast complete recovery. The other three four times slower and, more importantly, displayed only partial Only first comprises that are believed associated rafts. not caused topological constraints (microvilli, etc.), cytoskeletal constraints, or protein-protein interactions, because show 100% experiments 37°C. addition, raft-associated cannot coclustered antibodies on 12°C. interpretation best fits these data phase-separated system continuous (percolating) raft <25°C isolated domains nonraft dispersed, whereas 37°C becomes dispersed it.